1) Not only the study on the photo-stimulated luminescence, we investigated the prompt scintillation which is emitted on the nuclear radiation incidence. The ratio of photo-stimulated luminescence intensity to prompt scintillation intensity depends on the incident radiation kind and radiation energy. Also, this ratio is a function of specific energy loss (-dE/dx).2) Imaging plate can be succeedingly read many times. The ratio of each reading to the first reading depends on the incident radiation kind and energy. Then, we can roughly classify the kind and energy by taking the ratio.3) Very fine plutonium particle captured on a filter paper can be detected without any disturbance of radon and thoron daughters, and the particle size can be known.4) Distribution measurements of very small amount of radioactive contamination in a hot laboratory and radioactivity on a rock surface can be done in an ordinary atmosphere without using a shielding box. The detectable radioactivity was down to -10^<-3> Bq/mm^2.5) Extremely low level radioactivity distribution measurements were done for vegetables and meat in a graded shieding box with a thickness of 5-10cm of lead. This kind of results may give useful informations in the fields of botany, physiology, and archeology.5)野菜や食肉などのように我々の身辺に日常存在する材料の中に含まれる極微量の自然放射能の分布の測定を、鉛5〜10cm,あるいは鉄10〜20cmの厚さの遮蔽箱の中を段階遮蔽し、その最も内側を厚さ0.5〜1cmのアクリル樹脂で覆うことにより、上記の材料中に含まれる自然放射能の分布を測定することができた。